The invention discloses a preparation method for low-agglomeration antioxidant copper nanoparticle powder. The preparation method for the low-agglomeration antioxidant copper nanoparticle powder comprises the following steps of preparation: preparing copper salt solution and reductant-dispersant mixed liquor; reaction: dipping the copper salt solution into the reductant-dispersant mixed liquor, regulating the pH (potential of hydrogen) value to 10-13, keeping reaction at the temperature of 70-75DEG C under the ultrasonic oscillating condition until the reaction is finished, and standing to obtain a secondary precipitate; primary washing and filtering: obtaining the secondary precipitate; ultrasonic processing: adding surface protectant into the secondary precipitate, and standing after ultrasonic oscillating processing to obtain third precipitate; secondary washing and filtering: obtaining fourth precipitate; pre-drying: carrying out vacuum drying to the fourth precipitate to obtain copper powder; drying: adding NH4HCO3 into the obtained copper powder to be evenly mixed, putting the mixed copper powder under the flowing nitrogen atmosphere, and drying at the temperature of 70-80DEG C to obtain the copper nanoparticle powder. According to the preparation method for the low-agglomeration antioxidant copper nanoparticle powder, which is disclosed by the invention, the charging sequence is changed, ultrasonic vibration stirring is adopted, NH4HCO3 is added, and therefore the copper nanoparticle powder can be effectively prevented from being agglomerated and oxidized.